Greg Grunberg is currently guest-starring on CBS crime drama Criminal Minds and Showtime period drama Masters of Sex, but you’d likely recognize him from some of your favorite shows of the last 15 years. The childhood buddy of director J.J. Abrams is best known for starring roles in Felicity, Alias, and Heroes, as well as memorable turns on Lost and The Client List.

The actor recently guested on an episode of Criminal Minds as Chris Callahan, the husband of Agent Kate Callahan, played by Grunberg’s Love Bites and The Client List co-star Jennifer Love Hewitt. He also plays drums in Band from TV, which stars other primetime stars like Hugh Laurie, Jesse Spencer, and Teri Hatcher.

ET caught up with Grunberg at the 7th annual Valentine Romance Oscar Style Lounge & Party at Fig & Olive in West Hollywood, Calif., where the actor dished on acting alongside Hewitt once again and reuniting with Abrams for his top-secret role in Star Wars: The Force Awakens.

ETonline: You just guested on Criminal Minds, what has that storyline been like?

Greg Grunberg: It’s hard to deal with, where a child is going to be hurt is hard for me. I have three boys and it’s worrisome. You just have to try and stay on top of the social media your kids have. We will see how it plays out.

How many more episodes will you do?

It's open ended, depending on my schedule. I know I am coming back for at least one more in the spring.

How did you get to be a part of that show?

Via Jen Love Hewitt! We did a show together called Love Bites. We became really close pals. Whenever I have an opportunity to have a wife or girlfriend or sister [on a project], I always say, what about Love? She is usually busy, but this time it worked out!

I am so excited to even be in the movie! It’s going to be amazing. I can't say anything about it, J.J. [Abrams] always has this thing about the mystery box. But he has given out a little hints via charity. That’s really great. I am a huge Star Wars fan so to be in the movie was such a thrill.

The weird thing is, while we were shooting, they had these drones taking pictures overhead. They were taking pictures of these vehicles we had, which were in the first Star Wars! And we were like, really, what’s the sneaky need for those pictures then? I mean it’s cool to see where we were shooting, I guess. But I said to J.J., what kind of scoop are they getting if this was already exposed back in the 1970s?

Where were you shooting?

In London, I was there for six weeks. It was fantastic. Great cast, great crew.

We are best friends since when we were little kids, so every single day, every minute that wasn’t between action and cut, we were together, hanging out. It’s just a really unique situation to be able to work with your friend like that.

He calls you his lucky charm!

Well I don’t know about that! Yeah, it’s true. Nothing he ever does would be successful if it wasn’t for me! (laughs) He’s the best.

What’s your favorite memory you have of being together as kids?

Great question! I think always kicking his ass in any sport. Especially now! I always tease him, 'Oh yeah, you’re Mr. Big Shot now, but remember I beat you in H.O.R.S.E. when we were 11!' We used to make films and I would star in many of them. I have great memories.

What do you love about working with him?

His generosity and his loyalty. On any show, it starts from the top down. He is so in control, so prepared and so creative and makes decisions. He is just so good and wonderful with everyone. His instincts are so good. I have known that since I was 3!

Any word about you being on the new Heroes [miniseries, set to premiere on NBC in 2015]?

I am excited to see what is going to happen. I got a call from the creator of the show, asking if I would participate and I said absolutely. We will see! I will know very soon!

I have been talking to Adrian Pasdar about it, who is in my band. And just doing Hawaii Five-0, Masi [Oka] is in that. And at today’s event, James Kyson Lee was here and I just missed him! So we are all over the place!

Do you watch [former Heroes co-star] Hayden Panettiere on Nashville?

Of course! I’m like, she never sang with our band like that!

How is Hayden as a mom?

The best! She is the sweetest. She is a very genuine person. Can you imagine a little beautiful baby that can kick your ass? That’s pretty great!

We are doing a lot of charity work which is great. We love being able to raise money. We also have a new cool space in North Hollywood, it's a man cave. It's so great. We are streaming on Twitch and you can watch us rehearse every week!

Favorite vendor at tonight’s event?

I love Wednesday’s Child. It really changes the child unbelievably. It’s pretty special. I don’t come to an event unless there is a sincere charity angle to it.

What else are you working on right now?

I am writing a feature for Paramount. I have a TV series I am writing with [former Felicity co-star] Scott Foley for Shonda Rhimes’ company. And J.J. and I are always trying to work together.